The present invention relates to staircases and more specifically to the construction of adjustable modular staircases using step modules with respect to its overall rise and run.
It is well known in the art to have adjustable staircases. Yet, most of these adjustable staircases are only partially adjustable since they allow for a choice of two different staircase runs for a fixed staircase rise as described in U.S. Pat. No. 5,636,483 granted to Wille on Jun. 10, 1997. Another adjustable staircase provides only for a modular step rise adjustment with a fixed step run, thereby providing again two or three possible overall staircase runs for a fixed staircase rise as described in U.S. Pat. No. 5,502,933 granted to Skillern on Apr. 2, 1996 and U.S. Pat. No. 5,899,032 granted to Buzby on May 4, 1999; as long as the step rise remains within allowable limits dictated by various local building codes.
In order to have the flexibility to set the exact staircase run desired, within building code limits, for a fixed staircase rise, one must consider expensive and complicated staircase systems which may be neither affordable nor available for many average size house buildings.
It is also known to have partially prefabricated staircases that are finally assembled on the building yard site in order to ensure precise fitting of the staircase with the stairwell. Thus avoiding the extra cost associated to the risk of possible non-fitting of the entire prefabricated staircase with the stairwell, not even accounting for problems and cost encountered with the transportation of such large prefabricated staircase pieces.
Furthermore, with all known adjustable staircases of today, the treads are always positioned inwardly of the two stringers and forcing the final stairwell to have either full or short open (formed by the stringers themselves) walls on each side of the staircase, as opposed to completely open wall configuration.
It is therefore a general object of the present invention to provide an adjustable modular staircase of the character described which obviates the above noted disadvantages.
Another object of the present invention is to provide an adjustable modular staircase that allows for the selection of any staircase run, within building code limits, for a given staircase rise and vice versa.
Another object of the present invention is to provide an adjustable staircase that allows for the assembly of the staircase on site at the early stage of the building with rough tread surfaces that are covered by a proper surface finish later on in the building process.
A further object of the present invention is to provide an adjustable staircase that can be assembled in such a way that each side of the staircase is independently mounted either inwardly or outwardly of its stringer depending on the stairwell configuration within the building.
Another object of the present invention is to provide an adjustable modular staircase that reduces the complexity, the cost of the assembling of the staircase due to a reduced an amount of pieces added to prefabricated step modules provided in a wide variety of standard widths.
The present invention is directed to a modular staircase comprising:
two stringers for rigid attachment to a building structure in parallel, opposed relationship to each other;
a plurality of axially parallel pins protruding out of each of said stringers and spaced equidistant apart along said stringers, the pins in one stringer being axially aligned with the pins in the other stringer when installed in a building structure; and
a plurality of step modules, each step module including a tread and at least one end wall, said end wall having a top edge for supporting one end of the tread, a bottom edge inclined with respect to said top edge, and a notch in said bottom edge for releasably pivotally engaging one of said pins, whereby the step module can pivot around said pin to allow for horizontal leveling of each of the treads.
Preferably, each of said step modules includes a riser, said end wall supporting an end of said riser on a front edge thereof.
Preferably, each of said step modules includes horizontal supports extending rearwardly from a :bottom surface of said tread and vertical supports extending downwardly from a rear surface of said riser, when installed in a building structure, said horizontal supports of one step module abut the vertical supports of an upper, adjacent step module and said vertical supports of said one step module abut the horizontal supports of a lower adjacent step module, whereby said one step module is secured to said upper and lower adjacent modules by interconnecting said horizontal and vertical supports to vertical and horizontal supports of said upper and lower adjacent step modules, respectively.
Preferably, the staircase includes inclined holes in ends of said tread for securing said step module to a building structure,
Preferably, the staircase includes finishing plates for attachment to said tread, riser and end wall of each said step module to provide surface finish to said staircase.
Preferably, the finishing plate for said tread includes a convex tip for covering exposed edges of said tread, and a horizontal groove in an inner surface of said tip for engagement by a front edge of a tread to better secure said finishing plate of said tread.
Preferably, the tread finishing plate includes a thin layer of rigid material bonded up-side-down to a bottom surface of a finish material, thereby ensuring that said tread finishing plate has a slightly concave shape for better installation on said tread.
Preferably, the staircase, when installed in a building structure, the pins of one stringer extend toward the pins of the other stringer, whereby step modules can be mounted between stringers.
Alternatively, the staircase, when installed in a building structure, the pins of one stringer extend away from the pins of the other stringer, whereby said step modules overlap said stringers when installed.
Alternatively, the staircase, when installed in a building structure, all pins of said stringers extend in the same direction, whereby one end of each stop module is mounted inside of one stringer and the other end of each step module overlaps the other stringer.
Also, the present invention is directed to a staircase finishing kit for renovating the finishing of a step of an existing staircase, the kit comprises finishing plates for attachment to a tread, exposed end walls and a riser of said step to provide surface finish of the step, said finishing plate for said tread includes a convex tip for covering exposed edges of said tread, and a horizontal groove in an inner surface of said tip for engagement by a front edge of a tread to better secure said finishing plate of said tread.